Really Stuborn Acne

I'm 21 and I've had acne since I was 12! I'm getting really sick of it, every treatment I've tried doesn't work or backfires. First, it was mild and I used Dalacin T which cleared up my skin some but not completely. Deciding that it was ineffective, I used 10% benzoyl peroxide gels which turned out to be disastrous so I later went to visit a dermatologist who prescribed me doxycycline 100mg/day for 6 months along with brevoxyl and differin creams to use day and night. This was the most effective regimen I've had, my skin was clear after 2 months on this. But it didn't last long, and my acne came back after about a year on this regimen. So my dermatologist prescribed me Minocycline instead with the same creams (brevoxyl and differin). It didn't work at all, in fact I had a really bad rash on my jaw line so I stopped.
Recently, another dermatologist told me to try Isotrexine so I did. It seemed to work for awhile and then again, my face became worse than before which pustules popping up everywhere. I stopped that too and now my face is returning to its "normal" phase with acne on my cheeks, forehead and chin. I think I might be allergic to tetracyclines and even erythromycin or retinoids. What other option do I have??

[DILOPHOSAURUS]

I don't know about you but in my experience I have found some dermatologist just want to give you retn-a and send you packing. I have had the best luck going to a dermatologist that dose cosmetic surgery as well.  I felt like they had more ideas.  I don't know how common it is to find a dr like that who will see you for acne.  Because of were I live I found one but I am not sure if its like that in other places.   They were sorta rude on one occation, I think because they would rather be doing nose jobs but most of the time they were great.